Well, @PrestonSturges did say it was the day after. Though it is something you ingest, and it's entirely possible they were not only bad/not-very-strong mushrooms, but also stored improperly and so they got moldy or something and that's what got him sick. Entirely possible. This is why you know your sources (get references!) and inspect the product before ingestion. It's also why it's recommended to get whole caps and stems rather than ground. You can then grind yourself and make tea with it! Although in my opinion, eating them as-is is part of the fun and charm (it's totally gross).
I do wonder if he'd gotten any sleep yet (and more than just a doze). I'd also suggest against tripping when you have real responsibilities the next day. It'll color your trip, and make it harder for you to enjoy. It's a much better idea to trip when you have a totally free, aimless night at your disposal, with nothing at all to do the next day AND night except reflect and sleep (and I suggest eating and drinking your favorite food and drinks the day after a good trip, because they will be quite wonderful! And watch your favorite comedy in bed; it'll be hilarious and brand new!).
One time I made the rather fun mistake of eating some I had left in my freezer. "Oh, they've been there for two years. I bet they aren't any good any longer."
I could talk about this for days. I genuinely really enjoy hallucinating and even though it's been quite some time, I remember the last time vividly (which would be the fun mistake I just mentioned).